Aspirated blood cools off and lubricates the catheter system. The design of the Aspirex catheter does not allow recirculation of aspirated blood. In static in-vitro tests using human blood samples, aspiration with the Aspirex device was not associated with an increase in plasma free hemoglobin (24). Catheter introduction and thrombectomy mandate the use of a 12-French sheath inserted into the internal jugular or femoral vein. A pigtail or balloon-tipped catheter is required to place an exchange guide wire in the pulmonary artery. The Aspirex device is then introduced over the wire. An 80-cm 12-French sheath instead of a standard size 12-French sheath may be used to: 1) provide more support to introduce the Aspirex device into the pulmonary arteries, 2) to monitor right ventricular or pulmonary artery pressures, and 3) to inject contrast agent for pulmonary angiography. The distal part of the catheter shaft has enhanced flexibility, facilitating right heart passage and selective advancement into proximal pulmonary arteries (Table 1).